Fig. 125. United Wireless Receiving Set.
Two good circuits employing the double slide tuner are given in Fig. 123. Plates IV and V illustrate the oscillation or tuning circuits of the most prominent receptor systems.
If a loop aerial is used, more than one tuning coil is necessary as shown by the loop aerial oscillation circuits in Plate V.
Figs. 125 and 126 illustrate the instruments employed for receiving by the United Wireless Company.
Fig. 126. United Wireless Portable Receiving Set.
In Fig. 125 the handles which are attached to the sliders of the tuning coils project through long slots cut in the top and one side of the cabinet.
The tuning coils in the portable outfit are mounted in a vertical position in back of the aerial switch.
Loosely Coupled Tuning Coil.—By the use of a loosely coupled receiving tuner or transformer, the range of a station is considerably increased, as is also the strength of the signals, and much finer tuning and selectivity made possible.